Unequal stroke speed expansible chamber motor with independent admission and exhaust



Aprx 5, 1949. .1. CAREY 2,466,376

UNEQUAL STROKE ED EXPANSIBLE CHAMBER MOTOR WITH INDEPENDENT ADMISSIONAND EXHAUST Filed Jan. 6, 1945 2 sheets-sheet 1 sa l0 12a a y 75 69 5968 55 82 65 7,2 64 7/ 64 79 66 90 55 ,7,

,n v0' 'Vv' yy' r r r 85 76 I 6l 70 Ewik R 70 INVENTOR. 1S/[Jay CA 515a/ ATTO/NVE?.

April 5, 1949, L. J. CAREY UNEQUAL STROKE SPEED EXPANSIDLE CHAMBER MoToRWITH INDEPENDENT ADMISSION AND EXHAUST 2 Sheets-Sheet 2 Filed Jan. 6,1945 am mn. @R G @www Mmmm QS. SEVEN. EN EN y mv R. y E 1\ x QWAN? AE m?M [II N f mn 1 r D A. @y mm l QN vm w. J A y f f M 00,. mw rv E DE u* JEN ww W EN NE o. me. hm... E: .DE Q 02| Si WENN E Si D: Wm- Wm; 1. /I QQITN T/ l2. rn I -L I wm \\oo. E E# M ,M .12: wm M `m`\\|\\\ N2 Q" A I Q@E E: mo.

Patented Apr. 5, 1949 UNEQUAL STROKE SPEED EXPANSIBLE CHAMBER MOTOR WITHINDEPEND- ENT ADMISSION AND EXHAUST Leroy J. Carey, Cleveland, Ohio,assignor to The Marquette Metal Products Company, Cleveland, Ohio, acorporation of Ohio Application January 6, 1945, Serial No. 571,596

This invention relates to uid operated motors and more particularly to afluid operated motor in which the average speed of a reciprocating powertake-olf shaft or shafts diers for the respective opposite directions ofits travel during a complete working cycle.

The motor of this invention has a reciprocating piston assembly, is ofthe general type described and claimed in the copending application ofJohn H. Galley and Leroy J. Carey, Serial No. 548,692, led August 9,1944, now Patent No. 2,450,653, and possesses all of the advantages ofthe motor of said application such as large power output for unit sizeand weight, high efficiency, ease of manufacture, reliable operationeven when supplied with iiuid at extremely high pressures, simplicity ofstroke adjustment, and ability to function with gas or liquid as theoperating medium. In the preferred embodiment shown in the drawingshereof, a power take-off shaft disposed at one end of and forming a partof the reciprocating piston assembly is driven axially to and fro at thesame speed as the piston. Obvious modifications which are not shown inthe drawings include the use of a pair of power take-off shafts disposedrespectively at opposite ends of the piston and the use of a'rack andpinion driven valve actuating shaft as a power take-off shaft in themanner disclosed in the foregoing application. When provided withoppositely extending power take-off shafts, the motor is useable, forexample, to effect relative fast` and slow motion of machine toolcontrol elements.

Prior fluid motors of the type herein shown and having reciprocatingpistons or the like are unsuitable for many applications since thepiston speed and consequently the speed of the reciprocating powertake-off shaft or shafts are the same for the respective oppositedirections of travel. For example, it is desirable to drive, by means ofa fluid motor, a scraper or ductor (doctor) blade used for cleaning therolls of a steel strip rolling mill alternately back and forth axiallyof the roll. When the speed of the blade is the same for both directionsof travel, however, the foreign substances removed from the roll by theblade merely rest on the upper surface of the blade, move back and forththerewith, and 'must be removed by means such as a suction or'air blast.On the other hand, if the ductor blade is caused to move relatively fastin one direction and relatively slowin the other direction, the removedforeign substancesremain stationary with respect to the blade duringVthe fast move- 3 Claims. (Cl. 121-124) ment, travel with the bladeduring the slow movement, and consequently are translated axially of theroll until they reach one end of the roll and fall from the blade asinto a suitable waste receptacle.

The motor of the present invention is admirably suited for driving aductor blade as above described both because of the arrangement of itsreciprocatable power take-off shaft and because the speed of the shaftis relatively fast when moving in one direction and relatively slow whenmoving in the opposite direction. This desirable speed relationship isobtained by causing the effective area of a restricted portion orportions of the uid passages leading to a piston chamber at one end ofthe piston to differ from the effective area of a restricted portion orportions of the uid passages leading to a piston chamber at the oppositeend of the piston. The effective area of the restricted portion of theexhaust passage which is operative during slow movement of the pistonmay be so related to the effective area of the restricted portion of theinlet passage which is also operative during said slow'movement so thatthe restricted portions in the inlet and exhaust passages cooperate tostabilize the motor operation.

vAn object of this invention is to provide an improved fluid motor.

Another object is to provide a fluid motor having a reciprocating powertake-off shaft capable of moving at different speeds for the respectiveopposite directions of its travel during a working cycle.

A further object is to provide an improved valve mechanism for a fluidoperated motor.

Still another object is to provide a uid operated 'motor `havingalternately operative inlet valve ports of different sizes,respectively.

Another object is to provide a iiuid operated motor having alternatelyoperative inlet passages containing restricted portions of differentsizes, respectively.

vAmore specific object is to provide a fluid operated motor having valveports for admitting operating fluid for driving a power take-off shaftin opposite directions, respectively, the valve ports operative duringmovement of said shaft in one direction being different in size fromthose operative during movement of said shaft in the opposite direction.

Other objects include the provision of an improved packing means aroundan axially reciprocating power take-off shaft of a fluid operated motor,the provision of a novel piston and axially reciprocating power take-offassembly, and the provision of safety fluid passage means extendingthrough the power take-off shaft.

A further object is to provide a fluid motor in which the elfective areaof outlet and inlet passages are cooperatively related to cause stableoperation at relatively slow speeds.

Other objects and advantages of this invention will become apparent fromthe following description wherein reference is made to the drawings, inwhich Fig. 1 is a sectional view of the motor taken as indicated at I-Iin Fig. 2;

Fig. 2 and Fig. 3 are sectional views taken generally as indicated at2-2 of Figs. 1 and 4, and 3 3 of Fig. 1, respectively; and

Fig. 4 is a sectional view taken generally as indicated at 4-4 of Fig.2.

Referring to the drawings, a housing for the motor comprising anirregularly shaped body member IB which may be a cored casting or diecasting of any suitable metal or alloy or, for further example, aplastic molding, suitably formed and/or bored to accommodate the workingparts and to provide a minimum of wall thickness. The working parts ofthe motor comprise generally a reciprocatable piston assembly I I (Fig.3) including a power take-off shaft I2, a fluid flow control or valvemechanism (Fig. 2

principally) and a valve actuating assembly (Figs. 2, 3 and 4) which isdriven by the piston assembly for actuating the valve mechanism andwhich includes a snap-action or toggle mechanism I4 (Figs. 2 and 4)Considering particularly Fig. 3, the power takeoff shaft I2 is slidablyreceived for recipr-ocation within a central aperture I5 in aninternally recessed plug I6 threaded into acounter-bore formed at oneend of a cylinder bore I8 (Figs. l and 4 also) extending through thebody I0. An exteriorly threaded tubular extension co-axially with theaperture I5 and extending outwardly from an outer face surface 2I of theplug I6 has its interior wall surface spaced from the aperture I5 andthe shaft I2 to accommodate a suitable fluid seal. As shown, said sealcomprises a plurality of stacked elastic packing rings 22 ofconcave-convex section interposed between an outer convex face portion24 of a metal washer 25 and a concave inner end face 26 of a flangedsleeve or collar 28. The inner face portion of the washer 25 bearsagainst the surface 2l and the collar 28 has its flange received in ashouldered recess formed at the outer end of the extension 20. Acentrally apertured gland nut or thimble 29 loosely surrounds the shaftI2 and i5 threaded cn the extension 20 and forces the collar 28 intocompressing engagement with the rings 22.

A reduced inner end portion 30 of the shaft I2 is threaded into an endportion of a longitudinal bore 3I in a rack member 32 of the pistonassembly I I, a set screw 33 being provided if desired to secure thethreaded joint against loosening. The rack member 32 is slidablyreceived for reciprocation within a piston sleeve 34 pressed into thecylinder bore I8 and, intermediate of its ends, is of generallyrectangular cross section (Fig, 4) having teeth 35 on its upper surfacebut having a lower curved surface and completely cylindrical endportions complementary to the inner wall of the piston sleeve which maybe of high strength alloy if extremely high pressure fluid is to -beused.

A flexible sealing cup 36 is held in an annular shouldered recess at theshaft end of the rack member 32 by an integral flange on the inner endof the shaft I2, which flange thereby constitutes a piston head, and asecond sealing cup 36 is `similarly received in a shouldered recess atthe opposite end of the rack member 32 and is held therein by a pistonhead 39 threaded into an end portion of the bore 3I.

A Icentral axial bore 49 extending through the piston head 39 and acentral axial bore 4I extending into the inner end portion of the shaftI2 define a pair of valve seats 42 complementary respectively to a pairof ball valves 43 releasably held in seated position thereon by ahelical spring 44- interposed between the balls. A plurality oftransverse bores 4l in the race member 32 serve as fluid passages forfluid admitted into the bore 3| upon unseating of one or both of theballs 43 in a manner to be described later.

The cylinder bore I8 is sealed at its end opposite the shaft I2 by aninternally recessed castellated plug 45 threaded into a counterboredportion of the bore. The plugs I6 and 45 have respective inner chamferedportions bearing against and compressing annular elastic packings 43,respectively, seated on shoulders defined by the bottoms of therespective counterbcres. Piston chambers 48 and 49 are thereby formed atopposite ends of the rack member 32. It is readily apparent that, by amere interchange of parts, the shaft I2 may be operatively disposed atthe opposite end of the piston assembly II from the end at which shown,or that asecond shaft I2 and cooperating sealing assembly may replacethe piston head 29 and the plug 45 to form a motor having two oppositelydirected power take-off shafts.

Central bosses 5D and 5I in the recesses of the plugs I5 and 45,respectively, serve as stops for the piston assembly II when the motoris adjusted for maximum stroke operation. The boss 59, due to theaperture I5, is in the form of a hollow cylinder and has a plurality ofradial slots in its face defining ports 52 communicating, when thepiston assembly is in the position shown in Fig. 3, with mutuallyintersecting diametrical bores 53 and 54 in the shaft I2 which intersectthe inner end portion of the axial bore 4I.

Referring to Fig. 2, a pair of coaxial valve bores 55 in the body I()parallel to and above the cylinder bore I8 and opening into a recess 56respectively receive a pair of flanged valve guides in the form ofsleeves 58 and 59 constituting a part of the .valve assembly. The valveassembly additionally comprises aV pair of preferably similar valveVplungers 6i) and 6I slidably received for reciprocation in the sleeves58 and 59, respectively. The valve plungers are in a sense free floatingalthough caused to move simultaneously in opposite directions as thoughinterconnected. Each of the bores 55 has four portions of progressivelysmaller diameter inwardly of the housingrr I0 which dene three spacedshoulders 64, 65 and SI5 in each bore and each of the valve sleeves 58and 59 has outwardly projecting spaced annular flanges 63 and 69intermediately of its ends. The outermost portions of the bores 55 arethreaded to receive respective castellated plugs lll, reduced inner endsof which are piloted within the respective valve sleeves 58 and 59 toassist in holding the sleeves in coaxial relationship and centered inthe respective bore portions which receive the sleeves. Elastic ringpackings 'II are compressed between shouldered portions of the plugs 'I0and the shoulders 64 of the bores 55, respectively, and similarlpackings 12 are interposed between inner faces of the plugs 10 and theflanges 68 of the sleeves, respectively. In addition, elastic ringpackings 14 are inserted between the flanges 69 of the valve sleeves andthe respective bore shoulders 66. The machining dimensions between theplugs 10 and the respective valve sleeves 58 and 59 are such that beforemetal to metal contact therebetween occurs the packings 12 are squeezedout or extruded against the walls of the respective bores 55 and thepackings 14 are made thick enough so that they are compressed a.considerable amount at the same time that the packings 12 arecompressed. Thus by merely screwing the plugs 10 into position, thesleeves 58 and 59 ar-e properly positioned and the bores 44 sealedagainst fluid leakage.

An annular chamber 15 defined by a circumferential groove in the lefthand plug 10 (Fig. 2) communicates with the interior of the' valvesleeve 58 through radial passages 16 and an axial passage 18 in the plug10. A port 19 of relatively small size and a pair of diametricallyopposed ports 80 and 8| of relatively larger size than the port 19permit fluid to flow between the interior of the sleeve 58 and a chamber82 defined by the annular space around the sleeve 58 between the flanges68 and 69. Similarly, an annular chamber 84 defined by a circumferentialgroove in the right hand plug 10 (Fig. 2) communicates with the interiorof the sleeve 59 through radial passages 85 and an axial passage 86 inthe plug. A pair of diametrlcally opposed ports 88 and 89 of relativelysmall size and a pair of diametrically opposed ports 90 and 9| ofrelatively large size permit uid to flow between the interior of thesleeve 59 and a chamber 92 defined by the annular space around thesleeve 59, end walls for which space are formed by the flanges 68 and 69of the valve sleeve 59. The valve plungers 60 and 6| have respectiveinner portions 94 and 95, respectively, of reduced diameter adapted tocooperate with a push rod 96 of the valve actuating assembly. Theypreferred relationship of the sizes of the various ports 19, 80, 8| and88 to 9| will be more fully explained in subsequent consideration of theoperation of the motor.

Referring now to Fig. 4, the valve actuating assembly comprises arotatably supported shaft I disposed above and extending transversely ofthe rack member 32 within a recess |0| formed in a side face of the body0 and opening into the cylinder bore I8. The shaft I 00 has anintermediate non-circular portion (e. g.- squared) mounting a pinion |02which is in, contant mesh with the teeth 35 of the rack member 32 and issupported at its inner end portion by'a flanged bushing |04 pressed intoan aperture in an internal wall |05 of the body l0 between the recesses56 and IOI. A reduced outer end portion |06 of the shaft |00 issupported by a bearing member |01 held against an annular shoulder |08of the recess |0| by a plug |09 having spanner sockets ||0 and threadedinto the outer end portion of the recess. A washer having a relativelylarge central opening is disposed between the plug |09 and the bearingmember |01 and bears against an elastic packing 2 received in ashouldered recess of the bearing member. A seal around the shaft |00 isprovided by a cylindrical retainer I3 received in a complementary axialrecess in the inner side face of the bearing member |01 andhaving anannular shouldered recess adjacent the shaftcontaining an .elasticpacking ||4. End thrust of the shaft 001s takenzby an integralangeportion ||5 thereof'which bearsv against'the inner side face ofthebearing member |01 and the retainer ||3 and by engagement of the angeon the 4bushing |04 with a portion of the inner side face of the pinion|02.

It is obvious that if desired the shaft |00 may be extended beyond thebody I0 as in the above described application and serve as a. powertakeoff shaft instead of or in addition to the shaft I2.

yA longitudinally serrated portion 5 (Figs. 2 and 4) of theshaft |00 andadjacent the inner end thereof extends into the recess 56 and supportsin adjusted turned positions an index or drive plate ||6 having a,central splined (serrated)u opening ||8 ntting the shaft and suitablymounting inadjustable circumferentially spaced relation a pair ofoutwardly extending drive pins ||9 only one of which is illustrated.Alternate rotary movement of the shaft |00 causes turning of the plateH6 so that the drive pin ||9 alternately strikes a toggle arm 2|rotatably supported on a reduced inner end portion yof the shaft |00 andfreely turnable on said end portion.

T e toggle or snap action mechanism I5 includes an upwardly extendingtongue portion |22 of a cam |24, which latter is pivoted at its upperend to the arm |2| near the longitudinal center of said arm. The edgesof the tongue portion 22 and the top of the main body of the camdene'angularly disposed cam or shoulder surfaces |24a and |2411 ononeside'of the cam and cam or shoulder surfaces |240 and |2411 on theother side. The cam has parallel side edges below the surfaces |24b and|24d and has a lower triangular portion |25.

The arm 2| and the cam |24 are normally held in the right hand positionshown by solid lines in Fig. 2 (or in a similar left hand. position) dueto the combined bias of a helical tension spring |26 suitably secured atopposite ends to pins |28 andl |29, respectively, and of a similarspring |30 secured at its lower end to a xed pin |3| received in asocket in the body I0 and at its upper end to the mid-point of a lowerleg of a triangular hollow link |32. The link |32 has its upper vertexreceived adjacent the upper end of the spring |26 in an annular grooveformed near the outer end of the pin |28. The pins |28 and |29 aresuitably secured to and project rearwardly from the free end of the arm|2| and the lower end of the .cam I 24, respectively.

The push rod 96, shown (Fig. 4) as generally square in cross section,extends diametrlcally across the recess 56 and has its opposite endsslidably guided and supported,A as at rounded corner portions 96 of therod, in the inner ends of the valve guide bores of the valve sleeves 58and 59, respectively. segmental spaces for free flow of operating fluidaxially of the push rod 96 in either direction within the valve guidebores is provided by forming the rod as just described. A centralcut-away portion on the inner side of the push rod 96 provides space forthe cam |24 and defines somewhat pointed shoulders |34 and |35 (Fig. 2)adapted to be engaged bythe-cam surfaces |24a and |24b and by the camsurfaces |240 and |24d, respectively. Y v

A cover plate |36 (Figs. f1 and 4) forthe recess 56 is secured to thebody I0 as by -cap screws |38 which may be held against loosening bytie- Wires |39 (Fig. 1).

Operating fluid under pressure mayenter the motor through an inlet port|40 (left, Fig. 2) which communicates with a vertical passage, 4|

\ extending to the chamber 15 around one-of the` aeeasve plugs l0. lllhorizontal passage |42 intersects the passage |'4| and extends totheother. side of the motor where it intersects a vertical passage |43. Aneedle valve |44 having a knurled head |45 is threaded through a sidewall |46 Vof the body I and intersects .the passage I4| above the pointof intersection with the passage |42 and is arranged to be held inadjusted position by a nut |48.

A passage |49 (Figs. l and 2) extends from the chamber 82 to an axialgroove |50 (Figs. 1 and-3) in the wall whichcontains the cylinderforming sleeve 34. The groove |50 opens into an outer enlarged :portionof the piston chamber '48 defined by the recess in the inner face ofplug I6 (Fig. 3). Similarly, a passage |5| (Fig. 2 only) extends fromthe chamber 92 to an axial groove |52 (Fig. 3) which opens into anouterl enlarged portion of the piston chamber 49 defined by the recessin the inner face of the plug 45. The outer end ofthe passage |49 may besealed by aplug |54 (Fig. l), and a similar plug (not shown) seals theouter end of the passage I In event abnormally high pressure existsinthe piston chamber 49, ythe right hand ball 43 (Fig. 3) becomesunseated and fluid ows through the bore 40 into the bore 3| and thencethrough the transverse vbores 4l into a passage |55 (Fig. 4) to adischarge port |56 whereby the internal pressure is relieved. Should anabnormally high pressure condition exist in the piston chamber 48, `theleft hand ball 43 becomes unseated and fluid flows into the bore v3|through the radialv passages 53 and 54k and the axial passage 4I in theshaft I2. It will be noted that `even though the piston assembly is inthe extreme left hand position shown in Fig. 3, fluid at abnormalpressure can escape from the chamber 48 due to the provision of theradial slots 52 in the inner face surface of the boss 50 which slotscommunicate with the respectivepassages 52 and 53. A safety valve meansis thus provided which is operative regardless of the position of thepiston assembly and which prevents extremely high or abnormal pressurefluid from causing damage to the motor or to the apparatusdrivenfthereby. Discharge fluid received in the recess 56 flows freelyfrom said recess through la short bottom drain passage |58 (Fig. 2) intothe passage |55 and thence to the discharge port |55.

In considering the operation of the motor, the moving parts are assumedto be initially in the position in which shown by Figs. 2 and 3.

Operating fluid supplied in any suitable manner to the inlet port |40flows through the passage |4| past the needle valve |44, into theannular chamber "l5 and thence through the passages 1B and 18, theinterior of the valve sleeve 58 at the left of the plunger 60, throughthe single relatively small port 19, the chamber 82, and the bodypassages |49 and |50 tothe piston chamber 45. Concurrently, uid entersthe passages |42 and |43 and the passages 85 and 8S and exerts a staticpressure against the right hand end face of the plunger 5| which is heldin the position shown by the push rod 9B and the toggle mechanism I4.

Assuming first that the needle valve |44 is either not used or isadjusted toa position whereby its restrictive effect to fluid flow isless than that afforded by the port "i9, fluid flows relatively slowlythrough the port T9 so that fluid enters the chamber' 48 at a relativelyslow rate to force the piston assembly I to the right at a relativelyslow speed. As the pistonassembly I| movesfto reduce the volume of thechamber 49, fluid therein is forced through passages |52 and |5I intothe .annular groove 92 and thence through the passages 88 and 89 intothe space between the push'rodr `and the interior wall surface of thesleeve 59 from Where it flows freely into the chamber 56. It has beendetermined experimentally that steady and uniform slow motion of .thepiston assembly is obtained if the area of each of vthe ports v38 `and89 is made approximately equal to .the area of the port '|9. If the sizeofthe-ports V88 and 85 is increased beyond a certain limit, for exampleequal to the size of the ports and 8|, unstable and erratic operationoccurs vand the Vdesired slow speed is not obtained.

,As .the .pistonassembly II moves to the right, therack teeth 35vdrivethe pinion |02 counterclockwise (Fig. 3) to 'effect rotary Amovement ofthe shaft |00. Rotation of the shaft |00 counterclockwise rotates theindex or drive plate ||6 counterclookwiseas shown in Fig. 2 to cause oneof the drive pins |19 to rotate the toggle arm |2| counterclockwise fromthe position shown by the solid lines in Fig. 2 against the combinedbias of thesprings |26 and |30 tothe position shown by the broken linesin the same gure. It will `be noted that said broken line position isthe dead centerposition of the spring |25, but that said position isslightly beyond the dead center position of the spring |30. The cam |24is raised and shifted to the left'as indicated by said broken linesduring this portion of the movement of the arm |2I, but the camsurfaceI24a is not yet in contact with the end of the pointed shoulder 1340ithe push rod 96. However, the borner at the outer end of the cam surface|24@ is now in sliding contact with the lower beveled surface of thepointed shoulder |35 of the push rod 96 so that the latter still holdsthe valve plunger 6| in the initial position shown. Although thepressures on .the two valve plungers tending to force-the plungerstoward the push rod 96 are balanced, it should be observed that a slightdifference in Working clearance between the valve plungersfandtheirguide bores or foreign matter in the operating fluid would causeone of the plungers to move more freely in its guide bore than the otherplunger does, hence the importance of holding the push rod in positionwhile the toggle mechanism is moving from either extreme position to thedead center position at each half cycle of valve operation or duringea'chstroke of the snap action mechanism.

Shortly after the arm |2| has passed through the dead center position ofthe spring |28, the cam surface |2441I strikes the `end of the beveledportion |34 with a hammer blow, which moves the push rod 96 tothe left.Itis to be noted that bythe time the cam surface |240. and the shoulder|34 arein contact, the cam surface |24d has parted from the shoulder |35to permit movement of the pushrcd to the left. The toggle arm |2| andassociated parts continue to move counterclockwise due to the combinedbias of the springs.. |26 and |30 until an extreme left hand position isreached corresponding to the initial position ,of the toggle parts shownat the right in Fig.' 2 but not illustrated. Since the springs |24 and I30 do not have the same dead center position, there is no vposibility ofhesitation or stalling-during travelV of the arm |2I.

Movement of the push rod '96 to the left drives the valve plunger 60 tothe left to open the ports 00 Aand `ill and to'cut olf. Yatthe porty'ISthe -uid 9 pressure supply from the inlet port |40 to the pistonchamber 48. Concurrently, the valve plunger 6| moves to the left, due tothe direct connection of the passage 86 with the inlet port |40, andcloses the ports 88 and 99, and opens the ports 96 and 9| so that fluidflows from the passage 86 into the chamber 92 and through the passages(Fig. 2) and |52 (Fig. 3) into the piston chamber 49.

High pressure iiuid thus introduced into the chamber 49 returns thepiston assembly to its initial position at a higher rate of speed thanthat obtained during movement of the piston assembly to the right awayfrom its initial position. During such return movement, the rack teeth35 drive the shaft |00 clockwise (Fig. 2) and consequently the other ofthe spaced drive pins ||9 engages the toggle arm |21 and returns thelatter through a dead center position (not shown) with a snap action asbefore. The cam surface |24b holds the push rod 96 in its left handposition until just before the cam surface |240 strikes with a hammerblow against the shoulder |35, which operation occurs shortly after thedead center position of the spring |26 is passed. The valve plunger 6|is thus forced to its initial position by the push rod 96, and fluidpressure in the passage 18 simultaneously returns the left hand valveplunger 60 to its initial position.

During movement of the piston assembly to the left toward the positionshown, uid in the piston chamber 48 is discharged through the passages|50 and |49, the chamber 82, the ports 89 and 8|, the segmental spacesbetween the push rod 96 and the guide 59, the toggle-containing recess56, and the discharge passages |58 and |55 to the outlet or dischargeport |56 of the body I0. The ports 80 and 8| may be and preferably areeach of the same size as each of the ports 90 and 9|.

As more fully described in the above mentioned copending application,means may be provided for adjustably mounting the pins ||9 on the driveplate H6, so as to permit regulation of the length of the stroke of thepiston assembly and consequently of the shaft I2.

Selection of a valve sleeve 58 having a port 19 of given sizepredetermines the maximum possible speed of the shaft |2 during the slowspeed portion of its cycle. Speeds below this maximum slow speed may beobtained by adjusting the needle valve |44 so that the restrictive eiectprovided thereby in the passage |4| is greater than the restrictiveeffect provided by the port 19, it being apparent that the needle valve|44 is of no eifect which is less than that provided by the port 19.

I claim:

1. A fluid operated motor comprising a cylinder, a piston reciprocatablewithin said cylinder, piston chambers in said cylinder at opposite endsof said piston respectively, supply passages for conducting fluid underpressure into said chambers alternately to reciprocate said piston, flowcontrol means in said passages respectively having different operativeeffects on the flow of fluid thereby to cause the fluid to flow morefreely into one chamber than into the other chamber, one of said flowcontrol means comprising a fixed relatively restricted orice and anadjustable valve in series therewith relative to the flow of fluid inone only of the supply passages, and exhaust means for conducting fluidalternately from said chambers independently of said supply passages.

2. A fluid operated motor comprising a cylinder, a piston reciprocatablewithin said cylinder, piston chambers in said cylinder at opposite endsof said piston respectively, valve means for admitting uid underpressure into said chambers alternately to reciprocate said piston, saidmeans including orifice means for causing said fluid to enter into oneof said chambers at a faster rate than into the other of said chambers,valve means for conducting fluid from said chambers alternately as saidpiston recprocates, said last named means including orifice means forcausing the rate of flow of uid from said one of said chambers to beslower than from said other of said chambers, and a single meansoperatively connecting the piston to both valve means to operate themalternately.

3. In a fluid operated motor having a cylinder, a double ended pistonmounted for reciprocation in said cylinder, a rst valve mechanism forregulating the flow of fluid to and from said cylinder at one end ofsaid piston, a second valve mechanism for regulating the flow of fluidto and from said cylinder at the opposite end of said piston, mechanismoperated by said piston to control said valve alternately, thereby toeffect reciprocation of said piston, said flrst valve mechanism beingarranged to cause fluid to be admitted to said cylinder at a slower ratethan said second valve mechanism, and said first valve mechanism beingarranged to permit fluid to be exhausted from said cylinder at a fasterrate than said second Valve mechanism.

LEROY J. CAREY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATESy PATENTS Number Name Date 760,1'95 Green May 17, 1904799,577 Sage Sept. l2, 1905 841,527 Imler Jan. 15, 1907 1,622,029 DovelMar, 22, 1927 2,124,797 Rust et al July 26, 1938 2,160,920 Strawn June6, 1939 2,265,306 Orshansky Dec. 9, 1941 2,265,307 Orshansky Dec. 9,1941 2,302,352 MacNeil Nov. 17, 1942 2,332,664 Orshansky et al. Oct. 26,1943

